A method for integrated profile control and plugging removal in polymer flooding and injection wells

Abstract

The invention discloses an integrated operation system and method for polymer flooding and polymer injection well profile adjustment and plugging removal, which belongs to the technical field of polymer injection well profile adjustment and plugging removal in oil drilling and production technology. The invention comprises the following steps: artificial high permeability core and low permeability core are made, saturated water and saturated oil are evacuated from the high permeability core and the low permeability core, and the "high permeability core" and the "low permeability core" are connected in parallel to form a model to simulate the intra-layer and inter-layer heterogeneity of the oil reservoir, and then water flooding is performed at a constant speed, polymer solution is injected into the parallel model at a constant speed, and water flooding is performed subsequently to a water content of 90%; constant pressure P 调剖 Calcium chloride, spacer fluid and sodium silicate solution are injected alternately into the parallel model in multiple rounds. They contact and react in the high permeability layer to eventually generate silicate gel profile control agent; constant pressure P 解堵 Inject the unblocking working fluid into the parallel model and close the model for 12h to 36h; constant pressure P 后续水驱 Water was injected into the parallel model, followed by water flooding until the water cut reached 90%.

Description

Technical Field

[0001] The invention belongs to the technical field of profile control and plugging removal of polymer injection wells in petroleum drilling and production technology, and more specifically relates to an integrated operation method for profile control and plugging removal of polymer injection wells. Background Art

[0002] In recent years, with the rapid development of the national economy, my country's demand for oil has increased significantly, and major oil fields have an increasing demand for technologies to improve oil recovery rates.

[0003] In my country, most of the oil reservoirs are continental deposits with strong reservoir heterogeneity. During water flooding, the injected water will preferentially enter the high permeability layer with low seepage resistance (i.e., liquid absorption starting pressure), resulting in increased crude oil recovery and reduced seepage resistance. This will, on the one hand, cause a decrease in injection pressure (assuming the injection rate remains constant) and a decrease in the liquid absorption of the medium and low permeability layers; on the other hand, it will further increase the liquid absorption differential and liquid absorption of the high permeability layer. This will be repeated, and will eventually cause the injected water to circulate inefficiently and ineffectively in the high permeability layer, and a large amount of residual oil will be formed in the medium and low permeability layers due to the low degree of sweep.

[0004] In the prior art, polymer flooding technology is one of the effective methods to significantly improve the recovery rate of water-flooded oil reservoirs. Polymer flooding is to inject polymer solution into the water well. Polymer solution is a kind of macromolecular material. Like water injection, polymer solution will preferentially enter the high permeability layer of the reservoir and be retained, thereby generating additional seepage resistance and increasing the suction start pressure. Under the condition that the injection speed remains unchanged, the injection pressure of the whole well will increase, and the suction pressure difference and suction volume of the medium and low permeability layers will increase accordingly, thereby achieving the purpose of expanding the swept volume and improving the recovery rate; and, like the high permeability layer of the reservoir, the polymer solution will be retained and generate additional seepage resistance after entering the medium and low permeability layers, and the increase in additional seepage resistance, that is, the increase in suction start pressure, is much greater than that of the high permeability layer. Therefore, as the amount of polymer solution absorbed increases, the injection pressure of the whole well and the starting pressure of each small layer will continue to increase. Since the injection pressure of the whole well will be limited by the fracture pressure of the reservoir rock, once the fracture pressure is exceeded, cracks will be formed in the reservoir, which will cause the polymer solution to flow along the cracks, and finally affect the swept volume and polymer recovery. Therefore, during the polymer flooding process, the pressure difference of each small layer suction fluid shows a gradual decrease, especially in the low permeability layer, and finally even equals to zero, at which time the injection pressure is equal to the starting pressure of the small layer suction fluid. Practice has shown that the use of polymer flooding technology can increase the recovery rate by 5% to 15% on the basis of water flooding. However, after polymer flooding, about 60% of crude oil reserves are still not produced. They are mainly distributed in the medium and low permeability layers far away from the injection well, especially in the low permeability layer. Further measures to improve the recovery rate are urgently needed to mobilize this part of the remaining oil.

[0005] As mentioned above, polymer retention produces additional seepage resistance and causes an increase in the suction start pressure. In order to increase the suction pressure difference and suction volume of the low and medium permeability layers, it is necessary to decompose the polymer retained in the low and medium permeability layers, restore the permeability and reduce the suction start pressure. At present, the injection method of the working fluid for plugging removal in mines is usually general injection, and the actual plugging removal effect is poor. Analysis shows that the suction pressure difference of the high permeability layer, that is, the suction capacity, is much greater than that of the low and medium permeability layers, and the total volume of the plugging removal working fluid is small (100m 3 ~300m 3 ) and faster injection speed (0.5m 3 / min~1.5m 3 / min), the total construction time is short, so the amount of plugging removal working fluid absorbed by the medium and low permeability layers is very small, which is the fundamental reason for the poor plugging removal effect. In order to increase the amount of plugging removal working fluid absorbed by the medium and low permeability layers, the mine also tried to first adjust the profile to increase the seepage resistance of the high permeability layer and then inject the plugging removal process, and the profile control agent used is mostly polymer gel. However, this type of profile control agent has a high viscosity (generally greater than 100mPa·s), that is, it has the disadvantage of poor injectability, etc., which will cause a significant increase in injection pressure during mine construction. The profile control agent will inevitably enter the medium and low permeability layers, causing secondary damage.

[0006] That is, there is an urgent need for a technical solution for the profile control and unblocking operations of polymer flooding wells that can both improve the recovery rate and avoid problems such as blockage and secondary damage caused by the excessively high viscosity of the profile control agent used. Summary of the invention

[0007] The present invention aims to solve the above problems and provide a technical solution for the profile control and plugging removal operation of a polymer flooding well by alternately injecting calcium chloride solution, spacer fluid, sodium silicate solution and other aqueous agents into the deep high permeability layer of the reservoir for multiple rounds. Calcium chloride and sodium silicate are in deep contact and reaction to generate a silicate gel profile control agent. The extremely strong injection capacity of the aqueous agent is utilized to ensure that the profile control agent only enters the high permeability layer, thereby avoiding secondary damage to the medium and low permeability layers caused by the profile control agent, greatly increasing the amount of plugging removal working fluid absorbed by the medium and low permeability layers, thereby significantly improving the plugging removal effect.

[0008] The present invention first provides an integrated operation system for profile adjustment and unblocking of polymer flooding wells, including a horizontal flow pump for driving the liquid phase in the pipeline to flow, that is, the liquid phase material in the system is driven to flow along the pipeline by the horizontal flow pump, the horizontal flow pump is connected to an inlet four-way through a pipeline with a pressure sensor, and the inlet four-way is respectively connected to three intermediate containers arranged side by side through three independent pipelines each with a gate, that is, the liquid phase flows from the pressure sensor through the inlet four-way and is divided into three paths and flows into three intermediate containers respectively, and the three intermediate containers are provided with oil-displacing agents, and the replacement liquid in the pipeline enters the intermediate container under the drive of the horizontal flow pump to squeeze the oil-displacing agent in the intermediate container into the next unit, and the outlet ends of the three intermediate containers are also respectively connected through Three independent pipelines each with a gate are connected and gathered into an outlet four-way, that is, by opening and closing the independent gates on the three pipelines, the oil-displacing agent in different intermediate containers can be controlled to enter the next unit in time and quantity, so as to realize controllable circulation pumping, and the oil-displacing agent in the intermediate container can be the required water agent (such as calcium chloride solution, isolation liquid and sodium silicate solution), the output end of the outlet four-way is respectively connected to the two core clamps through a tee, and the inlet and outlet ends of each core clamp are provided with gates, and the bottom of the core clamp is provided with a produced liquid collector; and the pressure sensor, the inlet four-way, the intermediate container, the outlet four-way and the core clamp are all arranged in a 60°C insulation box.

[0009] Corresponding to the above system, the present invention also provides an integrated operation method for profile control and plugging removal of polymer flooding wells, comprising the following steps:

[0010] The core making step is to use quartz sand epoxy resin bonding method to make heterogeneous core test blocks in high permeability and low permeability layers. The two core test blocks are used as models to simulate the rocks in real flooding wells. The combination of the two core test blocks can restore the real environment.

[0011] More specifically, the outer dimensions of the core test block produced in the core production step are: width×height×length=4.5 cm×4.5 cm×30 cm.

[0012] Preferably, in the core making step, the permeability K of the high permeability core test block is g =500×10 -3 μm 2 ~10000×10 -3 μm 2 , the permeability of the low permeability core block K g =50×10 -3 μm 2 ~1000×10 -3 μm 2 .

[0013] The core measurement step is to measure the actual dimensions and volumes of the high-permeability and low-permeability core test blocks made in the core making step, respectively, and weigh the dry weight, and record the original masses of the two core test blocks for reference in subsequent processing; evacuate the saturated water from the two core test blocks, weigh the wet weight, calculate the saturated water volume and porosity of the core test blocks, that is, measure the masses of the two core test blocks in the water-saturated state; and saturate the two core test blocks with simulated oil under reservoir temperature conditions and let them stand for 24 hours, calculate the oil saturation, that is, measure the masses of the two core test blocks in the oil-saturated state. Since the innate conditions such as size and mass of the two core test blocks are unified, the measurement results of this step can be used as the original data of all the made core test blocks, and, wherein, the simulated oil can be compounded according to the actual use of crude oil and other types of oil;

[0014] In the constant-rate water flooding step, the high-permeability and low-permeability core blocks that have undergone the core measurement step are placed in parallel in the core holder, and water is injected into the core blocks at a constant rate until the water content in the core blocks reaches 80%, and the injection pressure P at the end of the water flooding is recorded. 水驱 ;

[0015] Preferably, in the constant speed water flooding step, the speed of injecting water into the core test block is 0.3 mL / min to 3 mL / min.

[0016] In the polymer flooding injection step, the polymer solution is first injected into the core test block after the constant water flooding step at a constant rate, and the injection pressure is increased to P 聚驱 When the polymer solution is continuously injected at a constant pressure, P 聚驱 =2P 水驱 ~3P 水驱 ;

[0017] Furthermore, in the polymer flooding injection step, the polymer solution is a mixed solution of one or more of ordinary polymers, temperature-resistant and salt-resistant monomer polymers, hydrophobic associating polymers, zwitterionic polymers, hyperbranched polymers and polysaccharide grafted polymers, and the polymer concentration of the polymer solution is 50 mg / L to 5000 mg / L, and the injection segment plug size is 0.1PV to 0.8PV.

[0018] The subsequent water flooding step uses the same P as in the polymer flooding injection step. 聚驱 The same constant pressure P 后续水驱 Inject water into the core block again until the water content of the core block reaches 90%;

[0019] The profile control agent injection step uses a constant pressure P 调剖Calcium chloride, spacer fluid and sodium silicate solution are alternately injected into the core test block after the subsequent water flooding step in several rounds, so that calcium chloride and sodium silicate are in contact with each other in the model high permeability layer and generate silicate gel, and finally the purpose of increasing the seepage resistance and the starting pressure of the liquid absorption is achieved, wherein P 水驱 <P 调剖 <0.5P 聚驱 ;

[0020] More specifically, in the step of injecting the profile control agent, the calcium chloride solution, the spacer solution, the sodium silicate solution, and the spacer solution are injected alternately into the core test block in 1 to 10 rounds in the order of each round;

[0021] Preferably, the concentration of the sodium silicate solution is 0.1% to 10%, the concentration of the calcium chloride solution is 0.1% to 10%, and the isolation liquid is water without calcium and magnesium ions;

[0022] More preferably, in the profile control agent injection step, the total injection slug size of calcium chloride, spacer fluid and sodium silicate solution is 0.01PV-0.2PV, and the slug size ratio of calcium chloride, spacer fluid and sodium silicate solution is 1:(0.15-0.25):1.

[0023] The plugging solution injection step uses a constant pressure P 解堵 Inject the plugging-removing working fluid into the core test block after the profile control agent injection step, then close the inlet and outlet gates at both ends of the core clamp for clamping the core test block to form a blocked well, soak the core test block in the plugging-removing working fluid environment for 12 to 24 hours, ensure that the plugging-removing working fluid can fully contact with the polymer retained in the low-permeability core, and finally achieve the purpose of decomposing the polymer, reducing the seepage resistance and reducing the starting pressure of the liquid absorption, wherein P 解堵 ≥1.2P 聚驱 .

[0024] Specifically, the plugging-removing working fluid includes a mixture of one or more of an inorganic plugging-removing agent, an organic polymer plugging-removing agent, and an organic colloid asphaltene plugging-removing agent.

[0025] More preferably, the inorganic plugging agent has a concentration of 0.5% to 30%, including one or more of hydrofluoric acid, hydrochloric acid, fluoroboric acid, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, trisodium hydroxyethylethylenediaminetriacetate, sodium nitrilotriacetic acid, citric acid, sodium D-gluconate, sodium polyacrylate, polyaspartic acid (sodium), hydrolyzed maleic anhydride, maleic acid-acrylic acid copolymer, polyepoxysuccinic acid, hydroxyethylated diphosphonic acid and diethylenetriamine penta (methylenephosphonic acid); the organic polymer plugging agent has a concentration of 0.5% to 15%, including one or more of potassium permanganate, β-cyclodextrin, sodium hypochlorite, ammonium persulfate, potassium persulfate and sodium perborate; the organic colloid asphaltene plugging agent has a concentration of 5% to 80%, including one or more of diesel, heptane, toluene, tetrahydrofuran, methyl pyrrolidone and petroleum ether.

[0026] In the subsequent water flooding step, constant pressure is used with the P 聚驱 The same constant pressure P 后续水驱 Water was injected into the core block again until the water content of the core block reached 90%.

[0027] Beneficial Effects

[0028] Compared with the prior art, the "silicate gel profile control + plugging removal" integrated operation method for improving oil recovery proposed in this patent application uses a silicate gel profile control agent, which is injected into the deep high permeability layer of the reservoir through multiple rounds of alternating injection of "calcium chloride solution, spacer fluid and sodium silicate solution". They contact and react in the deep oil layer to generate silicate gel profile control agent. Since the raw materials for generating the profile control agent are all water agents, they have extremely strong injection capacity (viscosity lower than 2mPa·s), which can ensure that the profile control agent only enters the high permeability layer, thereby avoiding secondary damage to the medium and low permeability layers caused by the profile control agent, greatly increasing the amount of plugging removal working fluid absorbed by the medium and low permeability layers, and significantly improving the plugging removal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The foregoing and following detailed description of the present invention will become more apparent when read in conjunction with the following drawings, in which:

[0030] Figure 1 It is a structural schematic diagram of the integrated operation system of the present invention;

[0031] Figure 2 It is a curve showing the relationship between injection pressure and PV number in the integrated operation method of the present invention;

[0032] Figure 3 It is a curve showing the relationship between water content and PV number in the integrated operation method of the present invention;

[0033] Figure 4It is a curve showing the relationship between the recovery factor and the PV number in the integrated operation method of the present invention;

[0034] Figure 5 It is a curve showing the relationship between the liquid extraction speed and the PV number in the integrated operation method of the present invention;

[0035] Figure 6 It is a curve showing the relationship between the diversion rate and the PV number in the integrated operation method of the present invention;

[0036] In the figure:

[0037] 1. Horizontal flow pump; 2. Pressure sensor; 3. Cross-way; 4. Intermediate container; 5. Gate; 6. Core holder. DETAILED DESCRIPTION

[0038] The technical solution for achieving the purpose of the present invention is further described below through specific embodiments. It should be noted that the technical solution claimed for protection by the present invention includes but is not limited to the following embodiments.

[0039] As a specific implementation scheme of the present invention, this example describes an integrated operation method for profile control and plugging removal of polymer flooding and injection wells, which specifically includes the following steps:

[0040] Core making steps: using quartz sand epoxy resin bonding method to make heterogeneous core blocks with high permeability and low permeability layers. The dimensions of the core blocks are: width × height × length = 4.5 cm × 4.5 cm × 30 cm. The permeability K of the high, medium and low layers in the high permeability core block is g 4500 / 2500 / 500×10 -3 μm 2 , the permeability K of the high, medium and low layers in the low permeability core block g 1000 / 500 / 250×10 -3 μm 2 .

[0041] The core measurement step is to measure the actual dimensions and volumes of the high permeability and low permeability core test blocks made in the core making step, respectively, and weigh the dry weight, and record the original masses of the two core test blocks for reference in subsequent processing; respectively, evacuate the saturated water of the two core test blocks and weigh the wet weight, calculate the saturated water volume and porosity of the core test blocks, that is, measure the masses of the two core test blocks in the water-saturated state, wherein the water used to evacuate the saturated water is the simulated injection water of the oil field, and the water quality is shown in Table 1:

[0042] Table 1

[0043]

[0044] And under reservoir temperature conditions, the two core test blocks were saturated with simulated oil and left to stand for 24 hours, and the oil saturation was calculated, that is, the masses of the two core test blocks under the oil saturation state were measured. In addition, the simulated oil was compounded by oilfield crude oil and white oil in proportion, and the viscosity was 18mPa·s at a reservoir temperature of 60°C.

[0045] In the constant-rate water flooding step, the high-permeability and low-permeability core blocks that have undergone the core measurement step are placed in the Figure 1 In the integrated operation system shown in FIG, water is injected into the two parallel core holders at a constant rate of 0.6 mL / min until the water content in the core block reaches 80%, and the injection pressure P is recorded at the end of water injection. 水驱 Among them, the integrated operation system is as follows Figure 1 As shown, it includes a horizontal flow pump 1 for driving the liquid phase in the pipeline to flow, that is, the horizontal flow pump 1 drives the liquid phase material in the system to flow along the pipeline, the horizontal flow pump 1 is connected to an inlet spool 3 through a pipeline with a pressure sensor 2, and the inlet spool 3 is respectively connected to three intermediate containers 4 arranged side by side through three independent pipelines each with a gate 5, that is, the liquid phase flows from the pressure sensor 2 through the inlet spool 3 and is divided into three paths and flows into the three intermediate containers 4 respectively, and the three intermediate containers 4 are provided with oil displacement agents, and the replacement liquid in the pipeline enters the intermediate container 4 under the drive of the horizontal flow pump 1 to squeeze the oil displacement agent in the intermediate container 4 into the next unit, and the outlet ends of the three intermediate containers 4 are also respectively connected through three independent pipes each with a gate 5. The three pipelines are connected and collected to an outlet spool 3, that is, by opening and closing the independent gates 5 on the three pipelines, the oil-displacing agents in different intermediate containers 4 can be controlled to enter the next unit in time and quantity, so as to realize controllable circulation pumping, and the oil-displacing agent in the intermediate container 4 can be the required water agent (such as calcium chloride solution, isolation liquid and sodium silicate solution), the output end of the outlet spool 3 is respectively connected to the two core clamps 6 through a tee, and the inlet and outlet ends of each core clamp 6 are provided with gates 5, and the bottom of the core clamp 6 is provided with a produced liquid collector; and the pressure sensor 2, the inlet spool 3, the intermediate container 4, the outlet spool 3 and the core clamp 6 are all arranged in a 60°C insulation box.

[0046] In the polymer flooding injection step, similarly, in the initial stage, 0.6 PV of polymer solution was injected into the core test block after the constant water flooding step at a constant rate of 0.6 mL / min. The polymer solution was a partially hydrolyzed polyacrylamide with an effective content of 90% and a polymer concentration of 1200 mg / L. The injection pressure P 聚驱 Increase to 2.5P 水驱 When changing to constant pressure 2.5P 水驱 Continue to inject the polymer solution, where P 聚驱 =2P 水驱 ~3P水驱 ; In addition, a DV-Ⅱ Brookfield viscometer was used to test the viscosity of the polymer solution, and the speed of the DV-Ⅱ Brookfield viscometer was set to 6r / min.

[0047] The subsequent water flooding step uses the same P as in the polymer flooding injection step. 聚驱 The same constant pressure P 后续水驱 (i.e. 2.5P 水驱 ) Water was injected into the core block again until the water content of the core block reached 90%.

[0048] The profile control agent injection step uses a constant pressure P 调剖 The core test block that has undergone the subsequent water flooding step is injected in five rounds in the order of calcium chloride solution, spacer fluid and sodium silicate solution, wherein calcium chloride and sodium silicate are 0.03PV or 0.06PV respectively, and the spacer water is 0.014PV, so that calcium chloride and sodium silicate are in contact in the model high permeability layer and generate silicate gel, ultimately achieving the purpose of increasing the seepage resistance and the starting pressure of the liquid absorption, and P 调剖 =1.5P 水驱 The concentrations of calcium chloride solution and sodium silicate solution are both 4%, and the isolation water is the same as the oil field simulated injection water in Table 1, and the simulated injection water does not contain calcium and magnesium ions.

[0049] The plugging solution injection step uses a constant pressure P 解堵 Inject the plugging-removing working fluid into the core test block after the profile control agent injection step, wherein P 解堵 =3P 水驱 The unblocking working fluid selected is potassium persulfate with a concentration of 1%, and then the inlet and outlet gates at both ends of the core clamp used to clamp the core test block are closed to form a stuffy well, and the core test block is soaked in the unblocking working fluid environment for 12 hours to ensure that the unblocking working fluid can fully contact with the retained polymer in the low-permeability core, ultimately achieving the purpose of decomposing the polymer, reducing the seepage resistance and reducing the suction starting pressure.

[0050] In the subsequent water flooding step, constant pressure is used with the P 聚驱 The same constant pressure P 后续水驱 (i.e. 2.5P 水驱 ) Water was injected into the core block again until the water content of the core block reached 90%.

[0051] In the above specific implementation process, the model injection pressure and the injection and production volume of each small layer are regularly recorded, the recovery factor, water content and small layer diversion rate are calculated, and the relationship curves of injection pressure, water content and recovery factor and PV number are drawn, and the relationship curve of small layer diversion rate and PV number is drawn.

[0052] The recorded results are as follows:

[0053] 1. Recovery rate

[0054] The data on the effect of profile control agent injection on the plugging removal effect after polymer flooding are shown in Table 2:

[0055] Table 2

[0056]

[0057] It can be seen from Table 2 that without profile control (Scheme 1), the final recovery rate of polymer flooding and plugging removal operations increased by 20.12%, and the recovery rate of plugging removal increased by only 0.70% (Scheme 1); under the silicate gel profile control, the recovery rates of polymer flooding and the comprehensive treatment measures of "profile control + plugging removal" increased by 27.82% and 32.31%, and the recovery rate of "profile control + plugging removal" increased by "6.18% + 1.41%" (Scheme 2) and "9.34% + 2.59%" (Scheme 3). It can be seen that the oil-increasing effect of the combined operation of "profile control + plugging removal" is significantly higher than that of the simple plugging removal measure, and the larger the size of the profile control agent segment plug, the better the oil-increasing effect of "profile control + plugging removal".

[0058] 2. Dynamic features

[0059] During the implementation process, the relationship curve between injection pressure and PV number is as follows: Figure 2 The relationship curve between moisture content and PV number is as follows: Figure 3 The relationship curve between recovery factor and PV number is shown in Figure 4 The relationship curve between the liquid collection speed and the PV number is as follows: Figure 5 ;from Figure 2 to Figure 5 It can be seen that due to the good injectability of silicate inorganic gel profile control agent and the auxiliary measure of reducing the injection speed to reduce the injection pressure, the profile control agent only enters the high permeability layer to achieve deep retention, thereby increasing the seepage resistance and the liquid absorption starting pressure.

[0060] In the subsequent unblocking process, the medium and low permeability layers not only increased the amount of unblocking agent absorbed at the injection end, but also significantly weakened the "cross-seepage" effect within the layer, the unblocking agent's action range increased, and the unblocking effect was improved, thereby achieving the purpose of expanding the swept volume and increasing the recovery rate. Further analysis found that compared with polymer flooding (Scheme 1), the liquid production rate after the "profile adjustment + unblocking" joint operation (Schemes 2 and 3) was also significantly reduced, effectively suppressing the inefficient and ineffective circulation of injected water after polymer flooding, and significantly reducing the cost of produced liquid treatment.

[0061] 3. Diversion rate

[0062] During the implementation process, the relationship curve between the diversion rate and the PV number at each stage is as follows: Figure 6 As shown in Table 3, the experimental data of the diversion rate of each stage of the small layer are as follows:

[0063]

[0064] From Table 3 and Figure 6 It can be seen that compared with the diversion rate at the production end after polymer flooding, after the "profile adjustment + plugging removal" joint operation measures are taken after polymer flooding, the diversion rate of the high permeability core block at the production end is reduced, and the diversion rate of the low permeability core block is increased, and the effect of expanding the swept volume is very obvious.

Claims

1. A method for integrated profile control and plugging removal in polymer flooding, characterized in that: The following steps are involved: The core making steps are to use quartz sand epoxy resin bonding method to make heterogeneous core test blocks with high permeability and low permeability layers; The core measurement step comprises measuring the actual dimensions and volumes of the high permeability and low permeability core test blocks prepared in the core preparation step, and weighing the dry weights; evacuating the saturated water from the two core test blocks, weighing the wet weights, and calculating the saturated water volume and porosity of the core test blocks; and saturating the two core test blocks with simulated oil under reservoir temperature conditions and leaving them to stand for 24 hours, and calculating the oil saturation; In the constant-rate water flooding step, the high-permeability and low-permeability core blocks that have undergone the core measurement step are placed in parallel in the core holder, and water is injected into the core blocks at a constant rate until the water content in the core blocks reaches 80%, and the injection pressure P at the end of the water flooding is recorded. 水驱 ; In the polymer flooding injection step, the polymer solution is first injected into the core test block after the constant water flooding step at a constant rate, and the injection pressure is increased to P 聚驱 When the polymer solution is continuously injected at a constant pressure, P 聚驱 =2P 水驱 ~3P 水驱 ; The subsequent water flooding step uses the same P as in the polymer flooding injection step. 聚驱 The same constant pressure P 后续水驱 Inject water into the core block again until the water content of the core block reaches 90%; The profile control agent injection step uses a constant pressure P 调剖 Calcium chloride, spacer fluid and sodium silicate solution are alternately injected into the core test block after the subsequent water flooding step in several rounds, so that calcium chloride and sodium silicate are in contact in the model high permeability layer and generate silicate gel, wherein P 水驱 <P 调剖 <0.5P 聚驱 Specifically, each round is injected into the core test block in the order of calcium chloride solution, spacer solution, sodium silicate solution, and spacer solution, in 1 to 10 rounds; the concentration of the sodium silicate solution is 0.1% to 10%, the concentration of the calcium chloride solution is 0.1% to 10%, and the spacer solution is water without calcium and magnesium ions; the total injection segment plug size of the calcium chloride, spacer solution and sodium silicate solution is 0.01PV to 0.2PV, and the segment plug size ratio of the calcium chloride, spacer solution and sodium silicate solution is 1:(0.15 to 0.25):1; The plugging solution injection step uses a constant pressure P 解堵 Inject the plugging-removing working fluid into the core test block after the profile control agent injection step, then close the inlet and outlet gates at both ends of the core clamp used to clamp the core test block to form a well, and soak the core test block in the plugging-removing working fluid environment for 12 to 24 hours, wherein P 解堵 ≥1.2P 聚驱 The unblocking working fluid comprises a mixture of one or more of an inorganic plugging agent, an organic polymer plugging agent and an organic colloid asphalt plugging agent; the inorganic plugging agent has a concentration of 0.5% to 30%, including hydrofluoric acid, hydrochloric acid, fluoroboric acid, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, trisodium hydroxyethylethylenediaminetriacetate, sodium nitrilotriacetic acid, citric acid, sodium D-gluconate, sodium polyacrylate, hydrolyzed maleic anhydride, maleic acid-acrylic acid copolymer, polyepoxysuccinic acid, hydroxyethyldiaminetetraacetic acid, Phosphonic acid and diethylenetriamine penta (methylene phosphonic acid) are compounded with one or more thereof; the concentration of the organic polymer plugging remover is 0.5% to 15%, including one or more of potassium permanganate, β-cyclodextrin, sodium hypochlorite, ammonium persulfate, potassium persulfate and sodium perborate; the concentration of the organic colloid asphaltene plugging remover is 5% to 80%, including one or more of diesel, heptane, toluene, tetrahydrofuran, methyl pyrrolidone and petroleum ether; the subsequent water flooding step adopts constant pressure and the P in the polymer flooding injection step 聚驱 The same constant pressure P 后续水驱 Water was injected into the core block again until the water content of the core block reached 90%.

2. The integrated method for profile control and plugging removal of polymer flooding wells according to claim 1, characterized in that: The outer dimensions of the core are: width×height×length=4.5 cm×4.5 cm×30 cm.

3. The integrated method for profile control and plugging removal of polymer flooding wells according to claim 1 or 2, characterized in that: In the core making step, the high permeability core permeability K g =500×10 -3 μm 2 ~10000×10 -3 μm 2 , low permeability core permeability K g =50×10 -3 μm 2 ~1000×10 -3 μm 2 .

4. The integrated method for profile control and plugging removal of polymer flooding wells according to claim 1, characterized in that: In the constant speed water flooding step, the speed of injecting water into the model is 0.3 mL / min to 3 mL / min.

5. The integrated method for profile control and plugging removal of polymer flooding wells according to claim 1, characterized in that: In the polymer flooding injection step, the polymer solution is a mixed solution of one or more of a temperature-resistant and salt-resistant monomer polymer, a hydrophobic associating polymer, a zwitterionic polymer, a hyperbranched polymer and a polysaccharide grafted polymer, and the polymer concentration of the polymer solution is 50 mg / L to 5000 mg / L, and the injection segment plug size is 0.1 PV to 0.8 PV.

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